﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Person
{
    class Person
    {
        private string name = null;
        private int? age = default(int);

        public string Name
        {
            get { return this.name; }
        }

        public int? Age
        {
            get { return this.age; }
        }

        public Person(string name, int? age)
        {
            this.name = name;
            this.age = age;
        }

        public override string ToString()
        {
            StringBuilder person = new StringBuilder();
            person.Append(this.name.ToString());
            if (this.age == null)
            {
                person.Append(String.Format("is unspecified years old"));
            }
            else
            {
                person.Append(String.Format("is {0} years old", this.age));
            }
            return person.ToString();
        }
    }
}
